A building entrance protector, i.e. junction box, provides an interface for cables from the central office of the service provider for distribution to subscribers throughout the building served by the junction box. A typical building entrance protector contains a protector field, which provides surge protection to each subscriber's line. Advantageously, the protector field comprises a panel having sockets thereon for plug-in protectors, which are solid state devices mounted on printed wiring board. A typical protector field has a five by five configuration. Due the need to conserve space within a junction box, the twenty-five plug-in protectors are placed abutting each other on the panel.
A plug-in protector has five terminals. A typical five-pin plug-in protector has a rectangular box shape housing measuring 1/2 inch wide, 3/4 inch high and 15/8 inch long. The housing of a prior art plug-in protector comprises a shell unit and a base unit. The shell unit has a hollow rectangular box shape body with an opening at the front portion. The rear portion of the body has an integral handle. Extending from the rear portion of the base unit is a printed wiring board containing surge protective devices. Connected to the printed wiring board and extending from the front portion of the base unit are pins for plugging into a protective field panel in a junction box for connection to and protection of a subscriber's line.
The rear portion of the base unit is inserted into the cavity of the shell unit, thereby enclosing the cavity opening, with the printed wiring board housed within the cavity of the shell unit. The base unit provides latches for engaging corresponding latch holes on the shell unit to maintain the unity of the shell and base units of the surge protector.
The size of the housing for plug-in protectors vary depending on the application and the type of components contained on the printed wiring board. Due to the limited space on a protector field panel, the only variable for expansion is the length. For prior art plug-in protectors, a larger sized printed wiring board requires a longer shell unit to accommodate the increase in length.
Therefore, there is a need for an improved housing for plug-in protectors that is easily expandable to accommodate different size of printed wiring board housed within the protectors.